Opioids, benzodiazepines, and muscle relaxants negatively affected outcomes of spinal cord stimulation (SCS) screening trials, an analysis presented here showed.
Patients who used opioids and sedating medications reported lower reductions in pain scores during SCS screening trials, according to Charles Odonkor, MD, of Massachusetts General Hospital in Boston, and colleagues, in a late-breaking presentation at the 2019 American Academy of Pain Medicine meeting.
Moreover, those treated with benzodiazepines and muscle relaxants also were likely to use higher doses of opioids.
Spinal cord stimulation is a neuromodulation therapy that uses a small implanted device to block pain signals by delivering electrical pulses to the spinal cord. Before a spinal cord stimulator is permanently implanted, patients often undergo a screening trial of about a week to test the effectiveness of the device during both rest and activity.
“In the wake of the opioid crisis, spinal cord stimulation therapy is rapidly emerging as a viable intervention and alternative for patients with chronic low back pain,” Odonkor said.
“Although clinical guidelines recommend tapering patients off their opioids prior to offering neuromodulation therapies, adherence to guidelines is variable,” he told MedPage Today.”Real-life data shows there are patients in practice receiving SCS who are concomitantly using opioids and sedating medications, even though prior studies have suggested that concomitant use of opioids and sedating medications is associated with serious morbidity and mortality.”
Benzodiazepines can increase the respiratory depressant effects of opioids: a recent review of health claims data showed that among opioid users, concurrent use of benzodiazepines more than doubled the risk of an overdose-related emergency room or inpatient visit. Both prescription opioids and benzodiazepines now carry FDA boxed warnings highlighting the dangers of using these drugs together.
In this retrospective analysis, Odonkor and colleagues studied 165 patients who underwent SCS screening trials. The team defined a successful trial as pain relief of ≥50% during the trial period. Overall, the trial success rate was 82% with a median duration of 7 days.
Patients who concomitantly used sedating medications and opioids had significantly lower reduction in pain scores during screening trials than patients not on those medications (55% vs 64% mean pain relief, P=0.048). Patients on morphine equivalent doses (MEDD) under 90 mg/day had a higher percentage of pain relief than those who used 90 mg/day MEDD or more (62% vs 49.9%, P=0.08).
Patients treated with sedating medications also used higher doses of opioids: 54.2 mg/day vs 24.6 mg/day MEDD (P=0.008). Overall, there was a trend towards higher failure rates among patients who used benzodiazepines, muscle relaxants, and opioids compared with patients who did not (20% vs 16%, P=0.054).
“Our research findings underscore a potential negative impact of opioids plus sedative medications on SCS outcomes,” Odonkor said. “It may be prudent for clinicians to have a conversation with their patients about why it may be important to wean them off sedative medications and opioids prior to attempting neuromodulation therapies.”
The study was limited by its observational nature and small sample size, the researchers noted. Screening trial details were not reported, and unknown confounders may have influenced results.
Despite many patients demonstrating long-term success with the devices, spinal cord stimulators account for the third-highest number of medical device injury reports to the FDA. More than 80,000 injury incidents have been flagged since 2008.
Odonkor reported no disclosures.